by Coomassie brilliant blue staining after SDS-PAGE on a 12 % polyacrylamide gel. The purified protein was stored in 5 % glycerol at -70°C. Electrophoretic mobility-shift assays (EMSAs) The EMSAs were performed as described previously [37]. The this website primers were labeled with T4 DNA polynucleotide kinase and the DNA fragments used for [γ-32P]-labeled probes were amplified by PCR, and then purified by using

to electrophoresis and autoradiography as described above. In order to quantify all probes, the probe DNA concentration was detected by ultraviolet spectrophotometer at the wavelength of 260 nm. DNase 1 footprinting To characterize the SabR-binding sites upstream region of sanG, a DNA fragment was amplified by PCR with the labeled primer EG1-F. The footprinting reaction mixture contained 30,000 cpm of [γ-32P]-labeled DNA probe, 6 ng to 0.3 μg of SabR-His6, 2.5 μg of poly-(dI-dC) (Sigma) and 20 mM Tris-base (pH 7.5), 1 mM DTT, 10 mM MgCl2, 0.5 μg calf BSA μl-1 and 5 % (v/v) glycerol in a total volume of 50 μl. After incubation of the mixture at 25°C for 25 min, 5.5 μl RQ1 RNase-free DNase Buffer and 0.1 U DNase 1 were added to the above reaction and the mixture was incubated for 1 min.